1. Field of the Invention
Embodiments of the present invention generally relate to the fabrication of integrated circuits. More particularly, embodiments of the present invention relate to a method and apparatus for processing a substrate that includes depositing an oxide rich cap on a low dielectric constant film.
2. Description of the Related Art
Semiconductor device geometries have dramatically decreased in size since such devices were first introduced several decades ago. Since then, integrated circuits have generally followed the two year/half-size rule (often called Moore's Law), which means that the number of devices that will fit on a chip doubles every two years. Today's fabrication plants are routinely producing devices having 0.13 μm and even 0.1 μm feature sizes, and tomorrow's plants soon will be producing devices having even smaller geometries.
In order to further reduce the size of devices on integrated circuits, it has become necessary to use conductive materials having low resistivity and to use insulators having low dielectric constants (k<4) to reduce the capacitive coupling between adjacent metal lines. Recent developments in low dielectric constant films have focused on incorporating silicon (Si), carbon (C), and oxygen (O) atoms into the deposited films.
The development of Si, C, and O containing films that have a very low dielectric constant as well as desirable thermal and mechanical properties has been challenging. Often, films made of a Si, C, and O network that have a dielectric constant less than 2.5 exhibit poor mechanical strength and are easily damaged by etch chemistry and subsequent plasma exposure, such as exposure to oxygen-containing plasmas, causing failure of the integrated circuit.
It has also been observed that very low dielectric constant films comprising silicon, carbon, and oxygen often have a hydrophobic surface that hinders the deposition of subsequent films on the surface of the low dielectric constant films and reduces the adhesion of the low dielectric constant films to subsequently deposited films.
Thus, there remains a need for a method of depositing low dielectric constant films with improved surface characteristics.